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Make the OS-level stdout/stderr capture work in the frontends.
Make the OS-level stdout/stderr capture work in the frontends.

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redirector_output_trap.py
93 lines | 3.2 KiB | text/x-python | PythonLexer
/ IPython / kernel / core / redirector_output_trap.py
# encoding: utf-8
"""
Trap stdout/stderr, including at the OS level. Calls a callback with
the output each time Python tries to write to the stdout or stderr.
"""
__docformat__ = "restructuredtext en"
#-------------------------------------------------------------------------------
# Copyright (C) 2008 The IPython Development Team
#
# Distributed under the terms of the BSD License. The full license is in
# the file COPYING, distributed as part of this software.
#-------------------------------------------------------------------------------
#-------------------------------------------------------------------------------
# Imports
#-------------------------------------------------------------------------------
from fd_redirector import FDRedirector, STDOUT, STDERR
from IPython.kernel.core.file_like import FileLike
from IPython.kernel.core.output_trap import OutputTrap
class RedirectorOutputTrap(OutputTrap):
""" Object which can trap text sent to stdout and stderr.
"""
#------------------------------------------------------------------------
# OutputTrap interface.
#------------------------------------------------------------------------
def __init__(self, out_callback, err_callback):
# Callback invoked on write to stdout and stderr
self.out_callback = out_callback
self.err_callback = err_callback
# File descriptor redirectors, to capture non-Python
# output.
self.out_redirector = FDRedirector(STDOUT)
self.err_redirector = FDRedirector(STDERR)
# Call the base class with file like objects that will trigger
# our callbacks
OutputTrap.__init__(self, out=FileLike(self.on_out_write),
err=FileLike(self.on_err_write), )
def set(self):
""" Set the hooks: set the redirectors and call the base class.
"""
self.out_redirector.start()
#self.err_redirector.start()
OutputTrap.set(self)
def unset(self):
""" Remove the hooks: call the base class and stop the
redirectors.
"""
OutputTrap.unset(self)
# Flush the redirectors before stopping them
self.on_out_write('')
self.err_redirector.stop()
self.on_err_write('')
self.out_redirector.stop()
#------------------------------------------------------------------------
# Callbacks for synchronous output
#------------------------------------------------------------------------
def on_out_write(self, string):
""" Callback called when there is some Python output on stdout.
"""
try:
self.out_callback(self.out_redirector.getvalue() + string)
except:
# If tracebacks are happening and we can't see them, it is
# quasy impossible to debug
self.unset()
raise
def on_err_write(self, string):
""" Callback called when there is some Python output on stderr.
"""
try:
self.err_callback(self.err_redirector.getvalue() + string)
except:
# If tracebacks are happening and we can't see them, it is
# quasy impossible to debug
self.unset()
raise